/Engine/Source/Runtime/MovieSceneTracks/Public/Tracks/MovieSceneCinematicShotTrack.h
The evaluation field is cached with the data and is invalidated if the data signature changes, or if this version number changes. You should bump this version number if you start/stop overriding, or otherwise change the logic, of PopulateEvaluationTree.
virtual int8 GetEvaluationFieldVersion() const